This invention relates to an apparatus for the treatment of fabrics with oxidizing gases. More particularly, there is provided an apparatus for treating fabrics in an extraction stage of a laundering operation with oxidizing gases such as ozone so as to decolorize dyes or coloring agents on the fabrics. The fabrics can be dry, wetted or in aqueous liquid.
The present invention is an improvement over the apparatus disclosed in U.S. Pat. No. 5,313,811, which is herein unincorporated by reference. The prior art apparatus requires a venturi system for introducing oxidizing gases into the processing vessel. Consequently, sufficient water must be present in order that a pump can push the water throughout the system, generate a vacuum and draw the oxidizing gas into the return pipe where it is blended with water and returned to the processing vessel.
In the cases where a desizing or abrasion step is run before or in conjunction with the oxidation, large amounts of dye are suspended in the water to operate the venturi. Therefore, the oxidizing agent attacks the dye in the return line between the venturi and the processing vessel. This occurrence decreases the efficiency in desizing and decolorizing garments or fabrics and increases the requirement for more oxidizing agent. Additionally, flowing water is required so that decolorization cannot be provided for dry or wetted garments.
Various other systems have been developed to treat fabric or garments with ozone. The systems generally use steam mixed with ozone enriched air or oxygen and the fabric or garments are suspended in a treatment chamber. The steam has the function of wetting the fabric or garments and to elevate the temperature to increase the reaction rate.
U.S. Pat. No. 1,823,352 to Crespi et al discloses an apparatus for bleaching textile fibers with a gaseous current, such as ozonized air. In the apparatus, textile material is suspended in a chamber where it is acted on by a gaseous ozonized air mixture which passes through the chamber.
U.S. Pat. No. 4,283,251 to Singh discloses a process relating to the ozone and peroxygen bleaching of cellulosic pulp. The process includes the steps of recycling extract effluent from the bleaching treatment.
U.S. Pat. No. 4,300,367 to Thorsen discloses the treatment of fibers with ozonexe2x80x94steam mixtures by conveying them through an open-ended chamber. The fibers are exposed to the ozonexe2x80x94steam mixture in the horizontal middle section of the chamber where the ozone is centrally introduced.
U.S. patent application Ser. No. 460,357 of Hall et al, which is herein incorporated by reference, discloses the fading of dyed cellulosic garments by the ozone degradation of the dye without any substantial degradation of the cellulosic materials in a vapor phase.
It should be understood that the term xe2x80x9cdyexe2x80x9d as used herein is meant to include any of the materials which are used to provide a color to a fabric such as conventional dyes, pigments, or the like. The term xe2x80x9cfabricxe2x80x9d as used herein is meant to include woven and non-woven cloth, knitted fabrics, garments, and the like.
A dry fabric or garment can contain up to about 5% moisture depending on atmospheric conditions.
In accordance with the invention there is provided a multi-purpose apparatus for laundering and selectively decolorizing a fabric, especially those containing cellulosic material having an oxidizable coloring agent such as a dye, pigment, organic or inorganic residues, and the like in a dry or wetted state or in a liquid. The fabric may comprise cotton, linen, or other bast fibers or rayon alone or in combination with other materials including natural and synthetic fibers, for example, wool, nylon, polyester, and the like.
The invention provides an apparatus for laundering and treating garments or fabrics with an oxidizing agent. The apparatus includes a housing having a chamber. The chamber contains a barrel or drum mounted for rotation in the chamber with means for rotating the barrel. Door means is provided on said housing for placing garments or fabrics into the chamber. Means is provided for introducing the oxidizing agent, which is a gas into the chamber. Pipe means associated with the chamber permits circulating the oxidizing gas into the chamber when required. There are means associated with the housing for introducing an aqueous fluid into the chamber and means for removing liquid from the chamber if required. The apparatus advantageously contains a microprocessor for selectively controlling the laundering cycles including washing, extracting, desizing, etc. with valves.
Advantageously, the oxidizing gas is introduced into the chamber through the door means.
The apparatus of the invention can be used to decolorize garments or fabrics having an oxidizable coloring agent by either placing an oxidizing gas in a liquid or treating the fabrics or garments with an oxidizing agent in a gaseous or vapor phase or both.
The apparatus is further capable of undergoing various laundering operations before or after treatment with an oxidizing agent, for example, desizing, extracting, washing and abrading.
The oxidizing agent can be gaseous or a liquid or a solid oxidant in a vapor state. Gaseous oxidizing agents include ozone, NOx and SOx. These gases can be used alone, in admixture or diluted with an inert or low reactive gas such as air. The oxidizing gases can be used in combination with steam or in an aqueous system.
The non-gaseous oxidants should be used in a vapor phase, preferably with wetted fabrics. More preferably, the non-gaseous oxidants are used in combination with steam.
The oxidant, for example, ozone primarily reacts with the colorant on the fabric when the fabric is wet. Therefore, the garment is wetted or treated in a wet state. The water content of the wetted fabric when treated is about 5 to 75% by weight, more preferably about 20 to 40% by weight or higher depending upon the degree of treatment, the type of oxidant and the effect desired. The process is performed in a chamber in which the oxidant is generally present in an amount of about 10 to 1000 mg. per liter, more preferably about 10 to 100 mg per liter. The temperature in the chamber of about 40 to 100 degrees C. Any excess oxidant emitted may be recycled back into the chamber or used to treat any effluent of the laundering process.
It is an object of the invention to provide an apparatus for use in a laundering operation to decolorize dyed garments or fabrics with an oxidant without degrading the fabric.
It is still further object of the invention to provide an apparatus for selectively and/or evenly decolorizing or fading dyed garments to produce fashion garments.
It is another object of the invention to provide an apparatus for use in a laundering operation which can desize, wash, extract and provide an oxidant to decolorize a colorant of a fabric or garment in a single chamber.
It is yet another object of the invention to provide an apparatus for decolorizing fabrics and garment where flowing water is not required.
Other objects and a fuller understanding of the invention will be had by referring to the following description and claims of a preferred embodiment, taken in conjunction with the accompanying drawings.